Mounting for arc lamps



March 1, 1932. E. A. WILLIFORD MOUNTING FOR ARC LAMPS Filed Sept" 7, 1929 2 Sheets-Sheet l kJVENTOR W ATTORNEYS- MaICh 1932- E. A WILLIFORD MOUNTING FOR ARC LAMPS Filed Sept. '7, 1929 2 Sheaets-Sheet Will W I NVENTOR Patented Mar. 1, 1932 UNITED STATES PATENTOFFICE-Q' EDXVARD A. WILLIFORD, OF LAKEWOOD, OHIO, ASSIGNOB TO NATIONAL CARBON COM- PANY, INC, A CORPORATIONOF NEW YORK MOUNTING FOR ARC LAMPS Application filed September 7, 1929. Serial No. 391,013.

My invention relates to a combined support and housing for lamps and especially to are lamps of the type used for therapeutic purposes or for illumination on the stages of theaters or in still and motion photography.

An object of my invention is to provide a lamp which shall permit of the use of two individually and adjustably supported carbon arcs in series with each other, yet employing w a common resistance, thus securing the efiicient operation of the twin arc lamp on orc inary commercial voltages and at the same time permit of individual adjustment in direction of the light from each lamp.

Another object of my invention is to provide a lamp housing structure which sh all permit of closure when the lamp is not in use thereby reducin the space occupied to a minimum and keeping the interior of the 1;- lamps free from dust or other objectionable substances.

A further object of my invention is to provide an improved reflector especially adapted for both therapeutic use and for still or mots tion photography. These and other objects of my invention will be apparent from the following specification having reference to the accompanying drawings in which I illustrate one embodiment of my invention and in which 3- Fig. 1 is a diagram showing the method of developing the reflector;

Fig. 2 is a plan view half in section taken on the line 2-2 of Fig. 3 of the lamp illustrating one embodiment of my invention;

Fig. 3 is a front view of the lamp in the open position;

Fig. 4- is a view of the lamp in closed position with the accompanying support and resistance;

Fig. 5 is a detail showing one side of a lamp house.

In these figures I show a lamp support comprising a base which may be provided with casters 11 for ease in moving it about. A

supporting member 12 is mounted on the base 10 and is preferably telescopic. This supporting member is provided with a pivot portion 13 which is preferably a prolongation of A the support 12 although I do not so limit myself. This pivot portion is conventionally formed by reducing the cross sectional area of the support 12 and also by providing a shoulder 14. A pair of lamp-houses 15 and 16 are mounted on the pivot portion by hinge members 17. Spacing members 18 are provided between the pairs of hinge members 17. The top of the support is provided with a screw threaded portion to receive a hand wheel19 which serves to clamp the hinge members and consequently the lamp houses in position. Each lamp-house is preferably in the shape of a frustum of a pyramid having a rectangular base. The hinge members are so posi-' tioned on the lamp-house that the front edge of the lamp-house lies in the same plane as the center of the pivot.

Within each lamphouse is a reflector 21 formed'of a curved sheet of metal. 'Thehorizontal cross section ofthis reflector is shown in detail in Fig. 1. The section comprises a central portion 22, which is a portion of a parabola p and marginal portions 23, which are portions of tangents t to the parabola. Electrode holding and feeding means 2 1 are provided being so situated that the electrode 25 passes just in front or behind the focus f of the parabola p. Each electrode feeding means is operated in a conventional manner by a solenoid in a housing 26 above the lamp house. Current is supplied to the electrodes through cables 27 which are so arranged that the electrodes are in series with each other and with a. resistance mounted within a casing 28 on the support. A ,conductor 29 is provided for connecting the lamp to any convenient source of electric current.

I may, if I so desire, employ a feeding mechanism in which both the upper and lower electrodes are fed towards each other. In this case the arc is held near the center and not merely in a vertical central plane and it is possible to use a reflector which is a surface of revolution, such, for example as would be formed by revolving the curve of Fig. 1 about its axis m-w.

While I have found the reflector of parabolic section a marked advantage, I do not limit myself thereto except to the extent indicated in the claims.

It will be seen that the lamps are individually adjustable since the hand wheel 19 may be loosened, unclamping the lamp-houses and permitting of the directing of the light about a vertical axis. Moreover, since the front 5 plane of the lamp-house passes through the center of the pivot and the lamps are in hori zontal alignment, it is evident that the lamphouses will meet when they are swung toward each other, thereby closing the lamp-houses to keep out dirt and other extraneous material and to form a compact unit. A I may provide any conventional fastening 31 for holding the lamp-houses together. When the lamps are spread apart and suitably directed upon the desired subject, as a patient for light treatment or a subject to be photographed, they are clamped in position by setting up on the hand wheel 19 thereby locking the lamphouses in position.

20 I may also make provision whereby the lamps may be individually adjusted about a horizontal as well as a vertical axis. While I'may employ any convenient method I have found that the middle hinge 17 can be pivoted to the lamp house and the upper and lower hinges provided with screws 31 extend ing through curved slots 32 in the side of the lamp house. Suitable nuts 33 are used to clamp the lamp house in its adjusted posi-- tion.

The shape of the reflector gives a concentrated central illuminated area due to the fact that the source of illumination is near the focus of the parabolic portion of the re 35 fiector. while the diverging tangential ends of the reflectorgive an increased area of diffuse illumination, thereby avoiding sharp shadows in photography.

I claim:

40 1. An arc lamp comprising a vertical support, a plurality of pairs of opposed hinges pivoted on said support, a pair of lamp houses, each lamp house being pivoted to one of the hinges of one of the pairs, and means on the hinges of the other pairs for clamping the lamp houses in position relatively to said hinges.

2. A lamp comprising a base; a support mounted on said base and provided with a pivot portion; a pair of lamp-houses pivoted to said pivot portion, said lamphouses being normally in horizontal alignment with each other and having their front edges in the same vertical plane as the pivot portion of the support, whereby the lamp-houses may be swung into'contact with each other; means for individually rotating said lamp-houses about a horizontal axis; a reflector within each lamp-house; and means for supporting asource of light before each reflector.

In testimony whereof, I afiix my signature.

EDWARD A. WILLIFORD. 

